... Notably, scientists haven’t found a link between signs of aging in hair and real aging in the body. A major study of 20,000 men and women in Copenhagen looked for any links between heart-disease mortality and physical signs of aging like gray hair, baldness and facial wrinkles. They found none.

“People with premature graying of the hair don’t die any sooner than anybody else,” said Dr. Leo M. Cooney, professor and chief of geriatrics at Yale University School of Medicine. “I think the study shows that gray hair has something to with your genetics and very little to do with premature aging...